Relationship Between a 700-MB "Dry/Wind" Index and Springtime Precipitation and Streamflow Within Four Snowmelt-Dominated Basins in Northern New Mexico and Southern Colorado.

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Relationship Between a 700-MB "Dry/Wind" Index and Springtime Precipitation and Streamflow Within Four Snowmelt-Dominated Basins in Northern New Mexico and Southern Colorado.

Author(s)

Jones, Kerry M.

Abstract

Climatic anomaly relationships that could potentially improve seasonal streamflow forecasts in southern Colorado and northern New Mexico were investigated through consideration of meteorological anomalies during the snow ablation season from 1980-2006. Historical relationships between (i) humidity and wind from March-June defined by an index developed for this study, denoted DWND; (ii) springtime precipitation; (iii) departures from expected seasonal streamflow; and (iv) El Niño-Southern Oscillation (ENSO) were examined within four sub-basins in southern Colorado and northern New Mexico: Upper San Juan above Pagosa Springs, Upper Rio Chama above El Vado Reservoir, and Embudo Creek/Rio Pueblo above Dixon. Potentially important links emerged between the DWND index and springtime precipitation. Namely, years that had well-above average DWND index values during April and May recorded below average precipitation if any at all, while years that had a lower average DWND index recorded near normal to much above normal precipitation. Furthermore, the relationship between the DWND index and Niño 3.4 anomalies is better defined than is the relationship between springtime precipitation and ENSO anomalies. This finding may increase confidence that cold (warm) phase ENSO extrema result in a greater (fewer) number of days characterized by low humidity and moderate to strong winds at high elevations in the San Juan and Sangre de Cristo mountains, thereby affecting snowpack and subsequent streamflow.

Description

A Professional Project Report submitted in partial fulfillment of the requirements for the degree of Master of Water Resources, Water Resources Program, University of New Mexico.